2 net_packet.c -- Handles in- and outgoing VPN packets
3 Copyright (C) 1998-2005 Ivo Timmermans,
4 2000-2014 Guus Sliepen <guus@tinc-vpn.org>
5 2010 Timothy Redaelli <timothy@redaelli.eu>
6 2010 Brandon Black <blblack@gmail.com>
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License along
19 with this program; if not, write to the Free Software Foundation, Inc.,
20 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
35 #include "connection.h"
52 #define MAX(a, b) ((a) > (b) ? (a) : (b))
55 /* The minimum size of a probe is 14 bytes, but since we normally use CBC mode
56 encryption, we can add a few extra random bytes without increasing the
57 resulting packet size. */
58 #define MIN_PROBE_SIZE 18
62 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
65 static void send_udppacket(node_t *, vpn_packet_t *);
67 unsigned replaywin = 32;
68 bool localdiscovery = true;
69 bool udp_discovery = true;
70 int udp_discovery_keepalive_interval = 10;
71 int udp_discovery_interval = 2;
72 int udp_discovery_timeout = 30;
74 #define MAX_SEQNO 1073741824
76 static void try_fix_mtu(node_t *n) {
80 if(n->mtuprobes == 20 || n->minmtu >= n->maxmtu) {
81 if(n->minmtu > n->maxmtu)
82 n->minmtu = n->maxmtu;
84 n->maxmtu = n->minmtu;
86 logger(DEBUG_TRAFFIC, LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
91 static void udp_probe_timeout_handler(void *data) {
93 if(!n->status.udp_confirmed)
96 logger(DEBUG_TRAFFIC, LOG_INFO, "Too much time has elapsed since last UDP ping response from %s (%s), stopping UDP communication", n->name, n->hostname);
97 n->status.udp_confirmed = false;
104 static void send_udp_probe_reply(node_t *n, vpn_packet_t *packet, length_t len) {
105 if(!n->status.sptps && !n->status.validkey) {
106 logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send UDP probe reply to %s (%s) but we don't have his key yet", n->name, n->hostname);
110 /* Type 2 probe replies were introduced in protocol 17.3 */
111 if ((n->options >> 24) >= 3) {
113 uint16_t len16 = htons(len);
114 memcpy(DATA(packet) + 1, &len16, 2);
115 packet->len = MIN_PROBE_SIZE;
116 logger(DEBUG_TRAFFIC, LOG_INFO, "Sending type 2 probe reply length %u to %s (%s)", len, n->name, n->hostname);
119 /* Legacy protocol: n won't understand type 2 probe replies. */
121 logger(DEBUG_TRAFFIC, LOG_INFO, "Sending type 1 probe reply length %u to %s (%s)", len, n->name, n->hostname);
124 /* Temporarily set udp_confirmed, so that the reply is sent
125 back exactly the way it came in. */
127 bool udp_confirmed = n->status.udp_confirmed;
128 n->status.udp_confirmed = true;
129 send_udppacket(n, packet);
130 n->status.udp_confirmed = udp_confirmed;
133 static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
134 if(!DATA(packet)[0]) {
135 logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request %d from %s (%s)", packet->len, n->name, n->hostname);
136 return send_udp_probe_reply(n, packet, len);
139 if (DATA(packet)[0] == 2) {
140 // It's a type 2 probe reply, use the length field inside the packet
142 memcpy(&len16, DATA(packet) + 1, 2);
146 logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d UDP probe reply %d from %s (%s)", DATA(packet)[0], len, n->name, n->hostname);
148 /* It's a valid reply: now we know bidirectional communication
149 is possible using the address and socket that the reply
151 n->status.udp_confirmed = true;
153 // Reset the UDP ping timer.
154 n->udp_ping_sent = now;
157 timeout_del(&n->udp_ping_timeout);
158 timeout_add(&n->udp_ping_timeout, &udp_probe_timeout_handler, n, &(struct timeval){udp_discovery_timeout, 0});
161 if(len > n->maxmtu) {
162 logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
165 /* Set mtuprobes to 1 so that try_mtu() doesn't reset maxmtu */
168 } else if(n->mtuprobes < 0 && len == n->maxmtu) {
169 /* We got a maxmtu sized packet, confirming the PMTU is still valid. */
171 n->mtu_ping_sent = now;
174 /* If applicable, raise the minimum supported MTU */
176 if(n->minmtu < len) {
182 static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
184 memcpy(dest, source, len);
186 } else if(level == 10) {
188 lzo_uint lzolen = MAXSIZE;
189 lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
194 } else if(level < 10) {
196 unsigned long destlen = MAXSIZE;
197 if(compress2(dest, &destlen, source, len, level) == Z_OK)
204 lzo_uint lzolen = MAXSIZE;
205 lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
215 static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
217 memcpy(dest, source, len);
219 } else if(level > 9) {
221 lzo_uint lzolen = MAXSIZE;
222 if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
230 unsigned long destlen = MAXSIZE;
231 if(uncompress(dest, &destlen, source, len) == Z_OK)
243 static void receive_packet(node_t *n, vpn_packet_t *packet) {
244 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Received packet of %d bytes from %s (%s)",
245 packet->len, n->name, n->hostname);
248 n->in_bytes += packet->len;
253 static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
255 return sptps_verify_datagram(&n->sptps, DATA(inpkt), inpkt->len);
257 #ifdef DISABLE_LEGACY
260 if(!n->status.validkey_in || !digest_active(n->indigest) || inpkt->len < sizeof(seqno_t) + digest_length(n->indigest))
263 return digest_verify(n->indigest, inpkt->data, inpkt->len - digest_length(n->indigest), inpkt->data + inpkt->len - digest_length(n->indigest));
267 static bool receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
268 vpn_packet_t pkt1, pkt2;
269 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
272 pkt1.offset = DEFAULT_PACKET_OFFSET;
273 pkt2.offset = DEFAULT_PACKET_OFFSET;
275 if(n->status.sptps) {
276 if(!n->sptps.state) {
277 if(!n->status.waitingforkey) {
278 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but we haven't exchanged keys yet", n->name, n->hostname);
281 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
285 n->status.udppacket = true;
286 bool result = sptps_receive_data(&n->sptps, DATA(inpkt), inpkt->len);
287 n->status.udppacket = false;
290 /* Uh-oh. It might be that the tunnel is stuck in some corrupted state,
291 so let's restart SPTPS in case that helps. But don't do that too often
292 to prevent storms, and because that would make life a little too easy
293 for external attackers trying to DoS us. */
294 if(n->last_req_key < now.tv_sec - 10) {
295 logger(DEBUG_PROTOCOL, LOG_ERR, "Failed to decode raw TCP packet from %s (%s), restarting SPTPS", n->name, n->hostname);
303 #ifdef DISABLE_LEGACY
306 if(!n->status.validkey_in) {
307 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
311 /* Check packet length */
313 if(inpkt->len < sizeof(seqno_t) + digest_length(n->indigest)) {
314 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got too short packet from %s (%s)",
315 n->name, n->hostname);
319 /* It's a legacy UDP packet, the data starts after the seqno */
321 inpkt->offset += sizeof(seqno_t);
323 /* Check the message authentication code */
325 if(digest_active(n->indigest)) {
326 inpkt->len -= digest_length(n->indigest);
327 if(!digest_verify(n->indigest, SEQNO(inpkt), inpkt->len, SEQNO(inpkt) + inpkt->len)) {
328 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
332 /* Decrypt the packet */
334 if(cipher_active(n->incipher)) {
335 vpn_packet_t *outpkt = pkt[nextpkt++];
338 if(!cipher_decrypt(n->incipher, SEQNO(inpkt), inpkt->len, SEQNO(outpkt), &outlen, true)) {
339 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
343 outpkt->len = outlen;
347 /* Check the sequence number */
350 memcpy(&seqno, SEQNO(inpkt), sizeof seqno);
351 seqno = ntohl(seqno);
352 inpkt->len -= sizeof seqno;
355 if(seqno != n->received_seqno + 1) {
356 if(seqno >= n->received_seqno + replaywin * 8) {
357 if(n->farfuture++ < replaywin >> 2) {
358 logger(DEBUG_ALWAYS, LOG_WARNING, "Packet from %s (%s) is %d seqs in the future, dropped (%u)",
359 n->name, n->hostname, seqno - n->received_seqno - 1, n->farfuture);
362 logger(DEBUG_ALWAYS, LOG_WARNING, "Lost %d packets from %s (%s)",
363 seqno - n->received_seqno - 1, n->name, n->hostname);
364 memset(n->late, 0, replaywin);
365 } else if (seqno <= n->received_seqno) {
366 if((n->received_seqno >= replaywin * 8 && seqno <= n->received_seqno - replaywin * 8) || !(n->late[(seqno / 8) % replaywin] & (1 << seqno % 8))) {
367 logger(DEBUG_ALWAYS, LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
368 n->name, n->hostname, seqno, n->received_seqno);
372 for(int i = n->received_seqno + 1; i < seqno; i++)
373 n->late[(i / 8) % replaywin] |= 1 << i % 8;
378 n->late[(seqno / 8) % replaywin] &= ~(1 << seqno % 8);
381 if(seqno > n->received_seqno)
382 n->received_seqno = seqno;
386 if(n->received_seqno > MAX_SEQNO)
389 /* Decompress the packet */
391 length_t origlen = inpkt->len;
393 if(n->incompression) {
394 vpn_packet_t *outpkt = pkt[nextpkt++];
396 if((outpkt->len = uncompress_packet(DATA(outpkt), DATA(inpkt), inpkt->len, n->incompression)) < 0) {
397 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while uncompressing packet from %s (%s)",
398 n->name, n->hostname);
404 origlen -= MTU/64 + 20;
407 if(inpkt->len > n->maxrecentlen)
408 n->maxrecentlen = inpkt->len;
412 if(!DATA(inpkt)[12] && !DATA(inpkt)[13])
413 udp_probe_h(n, inpkt, origlen);
415 receive_packet(n, inpkt);
420 void receive_tcppacket(connection_t *c, const char *buffer, int len) {
422 outpkt.offset = DEFAULT_PACKET_OFFSET;
424 if(len > sizeof outpkt.data - outpkt.offset)
428 if(c->options & OPTION_TCPONLY)
431 outpkt.priority = -1;
432 memcpy(DATA(&outpkt), buffer, len);
434 receive_packet(c->node, &outpkt);
437 bool receive_tcppacket_sptps(connection_t *c, const char *data, int len) {
438 if (len < sizeof(node_id_t) + sizeof(node_id_t)) {
439 logger(DEBUG_ALWAYS, LOG_ERR, "Got too short TCP SPTPS packet from %s (%s)", c->name, c->hostname);
443 node_t *to = lookup_node_id((node_id_t *)data);
444 data += sizeof(node_id_t); len -= sizeof(node_id_t);
446 logger(DEBUG_PROTOCOL, LOG_ERR, "Got TCP SPTPS packet from %s (%s) with unknown destination ID", c->name, c->hostname);
450 node_t *from = lookup_node_id((node_id_t *)data);
451 data += sizeof(node_id_t); len -= sizeof(node_id_t);
453 logger(DEBUG_PROTOCOL, LOG_ERR, "Got TCP SPTPS packet from %s (%s) with unknown source ID", c->name, c->hostname);
457 if(!to->status.reachable) {
458 /* This can happen in the form of a race condition
459 if the node just became unreachable. */
460 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot relay TCP packet from %s (%s) because the destination, %s (%s), is unreachable", from->name, from->hostname, to->name, to->hostname);
464 /* Help the sender reach us over UDP.
465 Note that we only do this if we're the destination or the static relay;
466 otherwise every hop would initiate its own UDP info message, resulting in elevated chatter. */
467 if(to->via == myself)
468 send_udp_info(myself, from);
470 /* If we're not the final recipient, relay the packet. */
473 send_sptps_data(to, from, 0, data, len);
478 /* The packet is for us */
480 if(!sptps_receive_data(&from->sptps, data, len)) {
481 /* Uh-oh. It might be that the tunnel is stuck in some corrupted state,
482 so let's restart SPTPS in case that helps. But don't do that too often
483 to prevent storms. */
484 if(from->last_req_key < now.tv_sec - 10) {
485 logger(DEBUG_PROTOCOL, LOG_ERR, "Failed to decode raw TCP packet from %s (%s), restarting SPTPS", from->name, from->hostname);
491 send_mtu_info(myself, from, MTU);
495 static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
496 if(!n->status.validkey && !n->connection)
502 if(!(DATA(origpkt)[12] | DATA(origpkt)[13])) {
503 sptps_send_record(&n->sptps, PKT_PROBE, (char *)DATA(origpkt), origpkt->len);
507 if(routing_mode == RMODE_ROUTER)
512 if(origpkt->len < offset)
517 if(n->outcompression) {
519 int len = compress_packet(DATA(&outpkt) + offset, DATA(origpkt) + offset, origpkt->len - offset, n->outcompression);
521 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)", n->name, n->hostname);
522 } else if(len < origpkt->len - offset) {
523 outpkt.len = len + offset;
525 type |= PKT_COMPRESSED;
529 /* If we have a direct metaconnection to n, and we can't use UDP, then
530 don't bother with SPTPS and just use a "plaintext" PACKET message.
531 We don't really care about end-to-end security since we're not
532 sending the message through any intermediate nodes. */
533 if(n->connection && origpkt->len > n->minmtu)
534 send_tcppacket(n->connection, origpkt);
536 sptps_send_record(&n->sptps, type, DATA(origpkt) + offset, origpkt->len - offset);
540 static void adapt_socket(const sockaddr_t *sa, int *sock) {
541 /* Make sure we have a suitable socket for the chosen address */
542 if(listen_socket[*sock].sa.sa.sa_family != sa->sa.sa_family) {
543 for(int i = 0; i < listen_sockets; i++) {
544 if(listen_socket[i].sa.sa.sa_family == sa->sa.sa_family) {
552 static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock) {
557 /* If the UDP address is confirmed, use it. */
558 if(n->status.udp_confirmed)
561 /* Send every third packet to n->address; that could be set
562 to the node's reflexive UDP address discovered during key
571 /* Otherwise, address are found in edges to this node.
572 So we pick a random edge and a random socket. */
575 int j = rand() % n->edge_tree->count;
576 edge_t *candidate = NULL;
578 for splay_each(edge_t, e, n->edge_tree) {
580 candidate = e->reverse;
586 *sa = &candidate->address;
587 *sock = rand() % listen_sockets;
590 adapt_socket(*sa, sock);
593 static void choose_local_address(const node_t *n, const sockaddr_t **sa, int *sock) {
596 /* Pick one of the edges from this node at random, then use its local address. */
599 int j = rand() % n->edge_tree->count;
600 edge_t *candidate = NULL;
602 for splay_each(edge_t, e, n->edge_tree) {
609 if (candidate && candidate->local_address.sa.sa_family) {
610 *sa = &candidate->local_address;
611 *sock = rand() % listen_sockets;
612 adapt_socket(*sa, sock);
616 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
617 vpn_packet_t pkt1, pkt2;
618 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
619 vpn_packet_t *inpkt = origpkt;
621 vpn_packet_t *outpkt;
622 int origlen = origpkt->len;
624 #if defined(SOL_IP) && defined(IP_TOS)
625 static int priority = 0;
626 int origpriority = origpkt->priority;
629 pkt1.offset = DEFAULT_PACKET_OFFSET;
630 pkt2.offset = DEFAULT_PACKET_OFFSET;
632 if(!n->status.reachable) {
633 logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
638 return send_sptps_packet(n, origpkt);
640 #ifdef DISABLE_LEGACY
643 /* Make sure we have a valid key */
645 if(!n->status.validkey) {
646 logger(DEBUG_TRAFFIC, LOG_INFO,
647 "No valid key known yet for %s (%s), forwarding via TCP",
648 n->name, n->hostname);
649 send_tcppacket(n->nexthop->connection, origpkt);
653 if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (DATA(inpkt)[12] | DATA(inpkt)[13])) {
654 logger(DEBUG_TRAFFIC, LOG_INFO,
655 "Packet for %s (%s) larger than minimum MTU, forwarding via %s",
656 n->name, n->hostname, n != n->nexthop ? n->nexthop->name : "TCP");
659 send_packet(n->nexthop, origpkt);
661 send_tcppacket(n->nexthop->connection, origpkt);
666 /* Compress the packet */
668 if(n->outcompression) {
669 outpkt = pkt[nextpkt++];
671 if((outpkt->len = compress_packet(DATA(outpkt), DATA(inpkt), inpkt->len, n->outcompression)) < 0) {
672 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)",
673 n->name, n->hostname);
680 /* Add sequence number */
682 seqno_t seqno = htonl(++(n->sent_seqno));
683 memcpy(SEQNO(inpkt), &seqno, sizeof seqno);
684 inpkt->len += sizeof seqno;
686 /* Encrypt the packet */
688 if(cipher_active(n->outcipher)) {
689 outpkt = pkt[nextpkt++];
692 if(!cipher_encrypt(n->outcipher, SEQNO(inpkt), inpkt->len, SEQNO(outpkt), &outlen, true)) {
693 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
697 outpkt->len = outlen;
701 /* Add the message authentication code */
703 if(digest_active(n->outdigest)) {
704 if(!digest_create(n->outdigest, SEQNO(inpkt), inpkt->len, SEQNO(inpkt) + inpkt->len)) {
705 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
709 inpkt->len += digest_length(n->outdigest);
712 /* Send the packet */
714 const sockaddr_t *sa = NULL;
717 if(n->status.send_locally)
718 choose_local_address(n, &sa, &sock);
720 choose_udp_address(n, &sa, &sock);
722 #if defined(SOL_IP) && defined(IP_TOS)
723 if(priorityinheritance && origpriority != priority
724 && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
725 priority = origpriority;
726 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
727 if(setsockopt(listen_socket[n->sock].udp.fd, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
728 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "setsockopt", sockstrerror(sockerrno));
732 if(sendto(listen_socket[sock].udp.fd, SEQNO(inpkt), inpkt->len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
733 if(sockmsgsize(sockerrno)) {
734 if(n->maxmtu >= origlen)
735 n->maxmtu = origlen - 1;
736 if(n->mtu >= origlen)
737 n->mtu = origlen - 1;
740 logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
744 origpkt->len = origlen;
748 bool send_sptps_data(node_t *to, node_t *from, int type, const void *data, size_t len) {
749 node_t *relay = (to->via != myself && (type == PKT_PROBE || (len - SPTPS_DATAGRAM_OVERHEAD) <= to->via->minmtu)) ? to->via : to->nexthop;
750 bool direct = from == myself && to == relay;
751 bool relay_supported = (relay->options >> 24) >= 4;
752 bool tcponly = (myself->options | relay->options) & OPTION_TCPONLY;
754 /* Send it via TCP if it is a handshake packet, TCPOnly is in use, this is a relay packet that the other node cannot understand, or this packet is larger than the MTU. */
756 if(type == SPTPS_HANDSHAKE || tcponly || (!direct && !relay_supported) || (type != PKT_PROBE && (len - SPTPS_DATAGRAM_OVERHEAD) > relay->minmtu)) {
757 if(type != SPTPS_HANDSHAKE && (to->nexthop->connection->options >> 24) >= 7) {
758 char buf[len + sizeof to->id + sizeof from->id]; char* buf_ptr = buf;
759 memcpy(buf_ptr, &to->id, sizeof to->id); buf_ptr += sizeof to->id;
760 memcpy(buf_ptr, &from->id, sizeof from->id); buf_ptr += sizeof from->id;
761 memcpy(buf_ptr, data, len); buf_ptr += len;
762 logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet from %s (%s) to %s (%s) via %s (%s) (TCP)", from->name, from->hostname, to->name, to->hostname, to->nexthop->name, to->nexthop->hostname);
763 return send_sptps_tcppacket(to->nexthop->connection, buf, sizeof buf);
766 char buf[len * 4 / 3 + 5];
767 b64encode(data, buf, len);
768 /* If this is a handshake packet, use ANS_KEY instead of REQ_KEY, for two reasons:
769 - We don't want intermediate nodes to switch to UDP to relay these packets;
770 - ANS_KEY allows us to learn the reflexive UDP address. */
771 if(type == SPTPS_HANDSHAKE) {
772 to->incompression = myself->incompression;
773 return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, from->name, to->name, buf, to->incompression);
775 return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, from->name, to->name, SPTPS_PACKET, buf);
780 if(relay_supported) overhead += sizeof to->id + sizeof from->id;
781 char buf[len + overhead]; char* buf_ptr = buf;
782 if(relay_supported) {
784 /* Inform the recipient that this packet was sent directly. */
785 node_id_t nullid = {};
786 memcpy(buf_ptr, &nullid, sizeof nullid); buf_ptr += sizeof nullid;
788 memcpy(buf_ptr, &to->id, sizeof to->id); buf_ptr += sizeof to->id;
790 memcpy(buf_ptr, &from->id, sizeof from->id); buf_ptr += sizeof from->id;
793 /* TODO: if this copy turns out to be a performance concern, change sptps_send_record() to add some "pre-padding" to the buffer and use that instead */
794 memcpy(buf_ptr, data, len); buf_ptr += len;
796 const sockaddr_t *sa = NULL;
798 if(relay->status.send_locally)
799 choose_local_address(relay, &sa, &sock);
801 choose_udp_address(relay, &sa, &sock);
802 logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet from %s (%s) to %s (%s) via %s (%s) (UDP)", from->name, from->hostname, to->name, to->hostname, relay->name, relay->hostname);
803 if(sendto(listen_socket[sock].udp.fd, buf, buf_ptr - buf, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
804 if(sockmsgsize(sockerrno)) {
805 // Compensate for SPTPS overhead
806 len -= SPTPS_DATAGRAM_OVERHEAD;
807 if(relay->maxmtu >= len)
808 relay->maxmtu = len - 1;
809 if(relay->mtu >= len)
810 relay->mtu = len - 1;
813 logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending UDP SPTPS packet to %s (%s): %s", relay->name, relay->hostname, sockstrerror(sockerrno));
821 bool receive_sptps_record(void *handle, uint8_t type, const void *data, uint16_t len) {
822 node_t *from = handle;
824 if(type == SPTPS_HANDSHAKE) {
825 if(!from->status.validkey) {
826 from->status.validkey = true;
827 from->status.waitingforkey = false;
828 logger(DEBUG_META, LOG_INFO, "SPTPS key exchange with %s (%s) succesful", from->name, from->hostname);
834 logger(DEBUG_ALWAYS, LOG_ERR, "Packet from %s (%s) larger than maximum supported size (%d > %d)", from->name, from->hostname, len, MTU);
839 inpkt.offset = DEFAULT_PACKET_OFFSET;
841 if(type == PKT_PROBE) {
842 if(!from->status.udppacket) {
843 logger(DEBUG_ALWAYS, LOG_ERR, "Got SPTPS PROBE packet from %s (%s) via TCP", from->name, from->hostname);
847 memcpy(DATA(&inpkt), data, len);
848 if(inpkt.len > from->maxrecentlen)
849 from->maxrecentlen = inpkt.len;
850 udp_probe_h(from, &inpkt, len);
854 if(type & ~(PKT_COMPRESSED | PKT_MAC)) {
855 logger(DEBUG_ALWAYS, LOG_ERR, "Unexpected SPTPS record type %d len %d from %s (%s)", type, len, from->name, from->hostname);
859 /* Check if we have the headers we need */
860 if(routing_mode != RMODE_ROUTER && !(type & PKT_MAC)) {
861 logger(DEBUG_TRAFFIC, LOG_ERR, "Received packet from %s (%s) without MAC header (maybe Mode is not set correctly)", from->name, from->hostname);
863 } else if(routing_mode == RMODE_ROUTER && (type & PKT_MAC)) {
864 logger(DEBUG_TRAFFIC, LOG_WARNING, "Received packet from %s (%s) with MAC header (maybe Mode is not set correctly)", from->name, from->hostname);
867 int offset = (type & PKT_MAC) ? 0 : 14;
868 if(type & PKT_COMPRESSED) {
869 length_t ulen = uncompress_packet(DATA(&inpkt) + offset, (const uint8_t *)data, len, from->incompression);
873 inpkt.len = ulen + offset;
875 if(inpkt.len > MAXSIZE)
878 memcpy(DATA(&inpkt) + offset, data, len);
879 inpkt.len = len + offset;
882 /* Generate the Ethernet packet type if necessary */
884 switch(DATA(&inpkt)[14] >> 4) {
886 DATA(&inpkt)[12] = 0x08;
887 DATA(&inpkt)[13] = 0x00;
890 DATA(&inpkt)[12] = 0x86;
891 DATA(&inpkt)[13] = 0xDD;
894 logger(DEBUG_TRAFFIC, LOG_ERR,
895 "Unknown IP version %d while reading packet from %s (%s)",
896 DATA(&inpkt)[14] >> 4, from->name, from->hostname);
901 if(from->status.udppacket && inpkt.len > from->maxrecentlen)
902 from->maxrecentlen = inpkt.len;
904 receive_packet(from, &inpkt);
908 // This function tries to get SPTPS keys, if they aren't already known.
909 // This function makes no guarantees - it is up to the caller to check the node's state to figure out if the keys are available.
910 static void try_sptps(node_t *n) {
911 if(n->status.validkey)
914 logger(DEBUG_TRAFFIC, LOG_INFO, "No valid key known yet for %s (%s)", n->name, n->hostname);
916 if(!n->status.waitingforkey)
918 else if(n->last_req_key + 10 < now.tv_sec) {
919 logger(DEBUG_ALWAYS, LOG_DEBUG, "No key from %s after 10 seconds, restarting SPTPS", n->name);
920 sptps_stop(&n->sptps);
921 n->status.waitingforkey = false;
928 static void send_udp_probe_packet(node_t *n, int len) {
930 packet.offset = DEFAULT_PACKET_OFFSET;
931 memset(DATA(&packet), 0, 14);
932 randomize(DATA(&packet) + 14, len - 14);
936 logger(DEBUG_TRAFFIC, LOG_INFO, "Sending UDP probe length %d to %s (%s)", len, n->name, n->hostname);
938 send_udppacket(n, &packet);
941 // This function tries to establish a UDP tunnel to a node so that packets can be sent.
942 // If a tunnel is already established, it makes sure it stays up.
943 // This function makes no guarantees - it is up to the caller to check the node's state to figure out if UDP is usable.
944 static void try_udp(node_t* n) {
948 /* Send gratuitous probe replies to 1.1 nodes. */
950 if((n->options >> 24) >= 3 && n->status.udp_confirmed) {
951 struct timeval ping_tx_elapsed;
952 timersub(&now, &n->udp_reply_sent, &ping_tx_elapsed);
954 if(ping_tx_elapsed.tv_sec >= udp_discovery_keepalive_interval - 1) {
955 n->udp_reply_sent = now;
956 if(n->maxrecentlen) {
958 pkt.len = n->maxrecentlen;
959 pkt.offset = DEFAULT_PACKET_OFFSET;
960 memset(DATA(&pkt), 0, 14);
961 randomize(DATA(&pkt) + 14, MIN_PROBE_SIZE - 14);
962 send_udp_probe_reply(n, &pkt, pkt.len);
970 struct timeval ping_tx_elapsed;
971 timersub(&now, &n->udp_ping_sent, &ping_tx_elapsed);
973 int interval = n->status.udp_confirmed ? udp_discovery_keepalive_interval : udp_discovery_interval;
975 if(ping_tx_elapsed.tv_sec >= interval) {
976 send_udp_probe_packet(n, MIN_PROBE_SIZE);
977 n->udp_ping_sent = now;
979 if(localdiscovery && !n->status.udp_confirmed && n->prevedge) {
980 n->status.send_locally = true;
981 send_udp_probe_packet(n, MIN_PROBE_SIZE);
982 n->status.send_locally = false;
987 static length_t choose_initial_maxmtu(node_t *n) {
992 const sockaddr_t *sa = NULL;
994 choose_udp_address(n, &sa, &sockindex);
998 sock = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
1000 logger(DEBUG_TRAFFIC, LOG_ERR, "Creating MTU assessment socket for %s (%s) failed: %s", n->name, n->hostname, sockstrerror(sockerrno));
1004 if(connect(sock, &sa->sa, SALEN(sa->sa))) {
1005 logger(DEBUG_TRAFFIC, LOG_ERR, "Connecting MTU assessment socket for %s (%s) failed: %s", n->name, n->hostname, sockstrerror(sockerrno));
1011 socklen_t ip_mtu_len = sizeof ip_mtu;
1012 if(getsockopt(sock, IPPROTO_IP, IP_MTU, &ip_mtu, &ip_mtu_len)) {
1013 logger(DEBUG_TRAFFIC, LOG_ERR, "getsockopt(IP_MTU) on %s (%s) failed: %s", n->name, n->hostname, sockstrerror(sockerrno));
1020 /* getsockopt(IP_MTU) returns the MTU of the physical interface.
1021 We need to remove various overheads to get to the tinc MTU. */
1022 length_t mtu = ip_mtu;
1023 mtu -= (sa->sa.sa_family == AF_INET6) ? sizeof(struct ip6_hdr) : sizeof(struct ip);
1025 if(n->status.sptps) {
1026 mtu -= SPTPS_DATAGRAM_OVERHEAD;
1027 if((n->options >> 24) >= 4)
1028 mtu -= sizeof(node_id_t) + sizeof(node_id_t);
1029 #ifndef DISABLE_LEGACY
1031 mtu -= digest_length(n->outdigest);
1033 /* Now it's tricky. We use CBC mode, so the length of the
1034 encrypted payload must be a multiple of the blocksize. The
1035 sequence number is also part of the encrypted payload, so we
1036 must account for it after correcting for the blocksize.
1037 Furthermore, the padding in the last block must be at least
1040 length_t blocksize = cipher_blocksize(n->outcipher);
1053 logger(DEBUG_TRAFFIC, LOG_ERR, "getsockopt(IP_MTU) on %s (%s) returned absurdly small value: %d", n->name, n->hostname, ip_mtu);
1059 logger(DEBUG_TRAFFIC, LOG_INFO, "Using system-provided maximum tinc MTU for %s (%s): %hd", n->name, n->hostname, mtu);
1069 /* This function tries to determines the MTU of a node.
1070 By calling this function repeatedly, n->minmtu will be progressively
1071 increased, and at some point, n->mtu will be fixed to n->minmtu. If the MTU
1072 is already fixed, this function checks if it can be increased.
1075 static void try_mtu(node_t *n) {
1076 if(!(n->options & OPTION_PMTU_DISCOVERY))
1079 if(udp_discovery && !n->status.udp_confirmed) {
1080 n->maxrecentlen = 0;
1087 /* mtuprobes == 0..19: initial discovery, send bursts with 1 second interval, mtuprobes++
1088 mtuprobes == 20: fix MTU, and go to -1
1089 mtuprobes == -1: send one maxmtu and one maxmtu+1 probe every pinginterval
1090 mtuprobes ==-2..-3: send one maxmtu probe every second
1091 mtuprobes == -4: maxmtu no longer valid, reset minmtu and maxmtu and go to 0 */
1093 struct timeval elapsed;
1094 timersub(&now, &n->mtu_ping_sent, &elapsed);
1095 if(n->mtuprobes >= 0) {
1096 if(n->mtuprobes != 0 && elapsed.tv_sec == 0 && elapsed.tv_usec < 333333)
1099 if(n->mtuprobes < -1) {
1100 if(elapsed.tv_sec < 1)
1103 if(elapsed.tv_sec < pinginterval)
1108 n->mtu_ping_sent = now;
1112 if(n->mtuprobes < -3) {
1113 /* We lost three MTU probes, restart discovery */
1114 logger(DEBUG_TRAFFIC, LOG_INFO, "Decrease in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
1119 if(n->mtuprobes < 0) {
1120 /* After the initial discovery, we only send one maxmtu and one
1121 maxmtu+1 probe to detect PMTU increases. */
1122 send_udp_probe_packet(n, n->maxmtu);
1123 if(n->mtuprobes == -1 && n->maxmtu + 1 < MTU)
1124 send_udp_probe_packet(n, n->maxmtu + 1);
1127 /* Before initial discovery begins, set maxmtu to the most likely value.
1128 If it's underestimated, we will correct it after initial discovery. */
1129 if(n->mtuprobes == 0)
1130 n->maxmtu = choose_initial_maxmtu(n);
1133 /* Decreasing the number of probes per cycle might make the algorithm react faster to lost packets,
1134 but it will typically increase convergence time in the no-loss case. */
1135 const length_t probes_per_cycle = 8;
1137 /* This magic value was determined using math simulations.
1138 It will result in a 1329-byte first probe, followed (if there was a reply) by a 1407-byte probe.
1139 Since 1407 is just below the range of tinc MTUs over typical networks,
1140 this fine-tuning allows tinc to cover a lot of ground very quickly.
1141 This fine-tuning is only valid for maxmtu = MTU; if maxmtu is smaller,
1142 then it's better to use a multiplier of 1. Indeed, this leads to an interesting scenario
1143 if choose_initial_maxmtu() returns the actual MTU value - it will get confirmed with one single probe. */
1144 const float multiplier = (n->maxmtu == MTU) ? 0.97 : 1;
1146 const float cycle_position = probes_per_cycle - (n->mtuprobes % probes_per_cycle) - 1;
1147 const length_t minmtu = MAX(n->minmtu, 512);
1148 const float interval = n->maxmtu - minmtu;
1150 /* The core of the discovery algorithm is this exponential.
1151 It produces very large probes early in the cycle, and then it very quickly decreases the probe size.
1152 This reflects the fact that in the most difficult cases, we don't get any feedback for probes that
1153 are too large, and therefore we need to concentrate on small offsets so that we can quickly converge
1154 on the precise MTU as we are approaching it.
1155 The last probe of the cycle is always 1 byte in size - this is to make sure we'll get at least one
1156 reply per cycle so that we can make progress. */
1157 const length_t offset = powf(interval, multiplier * cycle_position / (probes_per_cycle - 1));
1159 length_t maxmtu = n->maxmtu;
1160 send_udp_probe_packet(n, minmtu + offset);
1161 /* If maxmtu changed, it means the probe was rejected by the system because it was too large.
1162 In that case, we recalculate with the new maxmtu and try again. */
1163 if(n->mtuprobes < 0 || maxmtu == n->maxmtu)
1167 if(n->mtuprobes >= 0)
1172 /* These functions try to establish a tunnel to a node (or its relay) so that
1173 packets can be sent (e.g. exchange keys).
1174 If a tunnel is already established, it tries to improve it (e.g. by trying
1175 to establish a UDP tunnel instead of TCP). This function makes no
1176 guarantees - it is up to the caller to check the node's state to figure out
1177 if TCP and/or UDP is usable. By calling this function repeatedly, the
1178 tunnel is gradually improved until we hit the wall imposed by the underlying
1179 network environment. It is recommended to call this function every time a
1180 packet is sent (or intended to be sent) to a node, so that the tunnel keeps
1181 improving as packets flow, and then gracefully downgrades itself as it goes
1185 static void try_tx_sptps(node_t *n, bool mtu) {
1186 /* If n is a TCP-only neighbor, we'll only use "cleartext" PACKET
1187 messages anyway, so there's no need for SPTPS at all. */
1189 if(n->connection && ((myself->options | n->options) & OPTION_TCPONLY))
1192 /* Otherwise, try to do SPTPS authentication with n if necessary. */
1196 /* Do we need to statically relay packets? */
1198 node_t *via = (n->via == myself) ? n->nexthop : n->via;
1200 /* If we do have a static relay, try everything with that one instead, if it supports relaying. */
1203 if((via->options >> 24) < 4)
1205 return try_tx(via, mtu);
1208 /* Otherwise, try to establish UDP connectivity. */
1214 /* If we don't have UDP connectivity (yet), we need to use a dynamic relay (nexthop)
1215 while we try to establish direct connectivity. */
1217 if(!n->status.udp_confirmed && n != n->nexthop && (n->nexthop->options >> 24) >= 4)
1218 try_tx(n->nexthop, mtu);
1221 static void try_tx_legacy(node_t *n, bool mtu) {
1222 /* Does he have our key? If not, send one. */
1224 if(!n->status.validkey_in)
1227 /* Check if we already have a key, or request one. */
1229 if(!n->status.validkey) {
1230 if(n->last_req_key + 10 <= now.tv_sec) {
1232 n->last_req_key = now.tv_sec;
1242 void try_tx(node_t *n, bool mtu) {
1243 if(!n->status.reachable)
1246 try_tx_sptps(n, mtu);
1248 try_tx_legacy(n, mtu);
1251 void send_packet(node_t *n, vpn_packet_t *packet) {
1252 // If it's for myself, write it to the tun/tap device.
1256 memcpy(DATA(packet), mymac.x, ETH_ALEN);
1257 // Use an arbitrary fake source address.
1258 memcpy(DATA(packet) + ETH_ALEN, DATA(packet), ETH_ALEN);
1259 DATA(packet)[ETH_ALEN * 2 - 1] ^= 0xFF;
1262 n->out_bytes += packet->len;
1263 devops.write(packet);
1267 logger(DEBUG_TRAFFIC, LOG_ERR, "Sending packet of %d bytes to %s (%s)", packet->len, n->name, n->hostname);
1269 // If the node is not reachable, drop it.
1271 if(!n->status.reachable) {
1272 logger(DEBUG_TRAFFIC, LOG_INFO, "Node %s (%s) is not reachable", n->name, n->hostname);
1276 // Keep track of packet statistics.
1279 n->out_bytes += packet->len;
1281 // Check if it should be sent as an SPTPS packet.
1283 if(n->status.sptps) {
1284 send_sptps_packet(n, packet);
1289 // Determine which node to actually send it to.
1291 node_t *via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
1294 logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet to %s via %s (%s)", n->name, via->name, n->via->hostname);
1296 // Try to send via UDP, unless TCP is forced.
1298 if(packet->priority == -1 || ((myself->options | via->options) & OPTION_TCPONLY)) {
1299 if(!send_tcppacket(via->connection, packet))
1300 terminate_connection(via->connection, true);
1304 send_udppacket(via, packet);
1308 void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
1309 // Always give ourself a copy of the packet.
1311 send_packet(myself, packet);
1313 // In TunnelServer mode, do not forward broadcast packets.
1314 // The MST might not be valid and create loops.
1315 if(tunnelserver || broadcast_mode == BMODE_NONE)
1318 logger(DEBUG_TRAFFIC, LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)",
1319 packet->len, from->name, from->hostname);
1321 switch(broadcast_mode) {
1322 // In MST mode, broadcast packets travel via the Minimum Spanning Tree.
1323 // This guarantees all nodes receive the broadcast packet, and
1324 // usually distributes the sending of broadcast packets over all nodes.
1326 for list_each(connection_t, c, connection_list)
1327 if(c->edge && c->status.mst && c != from->nexthop->connection)
1328 send_packet(c->node, packet);
1331 // In direct mode, we send copies to each node we know of.
1332 // However, this only reaches nodes that can be reached in a single hop.
1333 // We don't have enough information to forward broadcast packets in this case.
1338 for splay_each(node_t, n, node_tree)
1339 if(n->status.reachable && n != myself && ((n->via == myself && n->nexthop == n) || n->via == n))
1340 send_packet(n, packet);
1348 /* We got a packet from some IP address, but we don't know who sent it. Try to
1349 verify the message authentication code against all active session keys.
1350 Since this is actually an expensive operation, we only do a full check once
1351 a minute, the rest of the time we only check against nodes for which we know
1352 an IP address that matches the one from the packet. */
1354 static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
1355 node_t *match = NULL;
1357 static time_t last_hard_try = 0;
1359 for splay_each(node_t, n, node_tree) {
1360 if(!n->status.reachable || n == myself)
1363 if(!n->status.validkey_in && !(n->status.sptps && n->sptps.instate))
1368 for splay_each(edge_t, e, n->edge_tree) {
1371 if(!sockaddrcmp_noport(from, &e->reverse->address)) {
1378 if(last_hard_try == now.tv_sec)
1383 if(!try_mac(n, pkt))
1391 last_hard_try = now.tv_sec;
1396 static void handle_incoming_vpn_packet(listen_socket_t *ls, vpn_packet_t *pkt, sockaddr_t *addr) {
1398 node_id_t nullid = {};
1400 bool direct = false;
1402 sockaddrunmap(addr); /* Some braindead IPv6 implementations do stupid things. */
1404 // Try to figure out who sent this packet.
1406 node_t *n = lookup_node_udp(addr);
1408 if(n && !n->status.udp_confirmed)
1409 n = NULL; // Don't believe it if we don't have confirmation yet.
1412 // It might be from a 1.1 node, which might have a source ID in the packet.
1413 pkt->offset = 2 * sizeof(node_id_t);
1414 from = lookup_node_id(SRCID(pkt));
1415 if(from && !memcmp(DSTID(pkt), &nullid, sizeof nullid) && from->status.sptps) {
1416 if(sptps_verify_datagram(&from->sptps, DATA(pkt), pkt->len - 2 * sizeof(node_id_t)))
1425 n = try_harder(addr, pkt);
1430 if(debug_level >= DEBUG_PROTOCOL) {
1431 hostname = sockaddr2hostname(addr);
1432 logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
1440 if(n->status.sptps) {
1441 bool relay_enabled = (n->options >> 24) >= 4;
1442 if (relay_enabled) {
1443 pkt->offset = 2 * sizeof(node_id_t);
1444 pkt->len -= pkt->offset;
1447 if(!memcmp(DSTID(pkt), &nullid, sizeof nullid) || !relay_enabled) {
1452 from = lookup_node_id(SRCID(pkt));
1453 to = lookup_node_id(DSTID(pkt));
1456 logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet from %s (%s) with unknown source and/or destination ID", n->name, n->hostname);
1460 if(!to->status.reachable) {
1461 /* This can happen in the form of a race condition
1462 if the node just became unreachable. */
1463 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot relay packet from %s (%s) because the destination, %s (%s), is unreachable", from->name, from->hostname, to->name, to->hostname);
1467 /* The packet is supposed to come from the originator or its static relay
1468 (i.e. with no dynamic relays in between).
1469 If it did not, "help" the static relay by sending it UDP info.
1470 Note that we only do this if we're the destination or the static relay;
1471 otherwise every hop would initiate its own UDP info message, resulting in elevated chatter. */
1473 if(n != from->via && to->via == myself)
1474 send_udp_info(myself, from);
1476 /* If we're not the final recipient, relay the packet. */
1479 send_sptps_data(to, from, 0, DATA(pkt), pkt->len);
1488 if(!receive_udppacket(from, pkt))
1491 n->sock = ls - listen_socket;
1492 if(direct && sockaddrcmp(addr, &n->address))
1493 update_node_udp(n, addr);
1495 /* If the packet went through a relay, help the sender find the appropriate MTU
1496 through the relay path. */
1499 send_mtu_info(myself, n, MTU);
1502 void handle_incoming_vpn_data(void *data, int flags) {
1503 listen_socket_t *ls = data;
1505 #ifdef HAVE_RECVMMSG
1507 vpn_packet_t pkt[MAX_MSG];
1508 sockaddr_t addr[MAX_MSG];
1509 struct mmsghdr msg[MAX_MSG];
1510 struct iovec iov[MAX_MSG];
1512 for(int i = 0; i < MAX_MSG; i++) {
1515 iov[i] = (struct iovec){
1516 .iov_base = DATA(&pkt[i]),
1520 msg[i].msg_hdr = (struct msghdr){
1521 .msg_name = &addr[i].sa,
1522 .msg_namelen = sizeof addr[i],
1528 int num = recvmmsg(ls->udp.fd, msg, MAX_MSG, MSG_DONTWAIT, NULL);
1531 if(!sockwouldblock(sockerrno))
1532 logger(DEBUG_ALWAYS, LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
1536 for(int i = 0; i < num; i++) {
1537 pkt[i].len = msg[i].msg_len;
1538 if(pkt[i].len <= 0 || pkt[i].len > MAXSIZE)
1540 handle_incoming_vpn_packet(ls, &pkt[i], &addr[i]);
1544 sockaddr_t addr = {};
1545 socklen_t addrlen = sizeof addr;
1548 int len = recvfrom(ls->udp.fd, DATA(&pkt), MAXSIZE, 0, &addr.sa, &addrlen);
1550 if(len <= 0 || len > MAXSIZE) {
1551 if(!sockwouldblock(sockerrno))
1552 logger(DEBUG_ALWAYS, LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
1558 handle_incoming_vpn_packet(ls, &pkt, &addr);
1562 void handle_device_data(void *data, int flags) {
1563 vpn_packet_t packet;
1564 packet.offset = DEFAULT_PACKET_OFFSET;
1565 packet.priority = 0;
1567 if(devops.read(&packet)) {
1568 myself->in_packets++;
1569 myself->in_bytes += packet.len;
1570 route(myself, &packet);